A good method of discovery is to imagine certain members of a system removed and then see how what is left would behave: for example, where would we be if iron were absent from the world: this is an old example.

Ask yourself always: how can this be done better?

Just as there are polysyllabic words that say very little, so there are also monosyllabic words of infinite meaning.

Before we blame we should first see whether we cannot excuse.

Reason now gazes above the realm of the dark but warm feelings as the Alpine peaks do above the clouds. They behold the sun more clearly and distinctly, but they are cold and unfruitful.

What you have been obliged to discover by yourself leaves a path in your mind which you can use again when the need arises.

Those who never have time do least